we are tyco integrated security. and we are sharper. >>> welcome back for live continuing coverage from boston. we have more breaking news tonight. a letter that tested positive for poisoned rice was reviewed in the capitol's mail facility in washington. they said the letter did test positive for rice and it was addressed to the office of republican senator roger wicker of mississippi. the letter is undergoing further testing. senator wicker now has a protective detayil assigned to him. we have dana bash live. the initial testing was positive. further testing is going on now. what's the latest you've heard? >> well, anderson, we can now report from the senate sergeant in arms terry gaynor that the envelope did test positive today at the actual lab, so they feel confident at this point that it is a positive test for rice. they had the initial test, as you pointed out, in the field office which historically are not that reliable but this was done in the actual lab. the other things we can report are the mysterious mark